Electromagnetically controlled friction clutch

ABSTRACT

A spring set and electromagnetically released friction brake, preferably for electric motors, has an exteriorly threaded sleeve coaxially spaced from the magnetic armature disc which is magnetically attracted toward the releasing position. A ringshaped abutment structure surrounds the sleeve and is held in an adjusted position relative to the sleeve by means of a ring which is seated on the sleeve in threaded engagement therewith. One end of each brake pressure spring is in pressure engagement with the armature disc. The other end bears against the abutment structure. Rotating the ring on the sleeve causes the ring to shift axially and thereby also displaces the abutment structure to adjust the spring force. The threaded ring is prevented from inadvertent rotation by having marginal recesses engaged by leaf springs which are fastened to the ring-shaped abutment structure and are lifted out of the recesses when a tubular wrench or the like tool is pushed over the ring for the purpose of turning it.

Unlted States Patent 1111 ,55

[72] Inventors Wilhelm Ritter FOREIGN PATENTS Bad Neuswdt 5881c, 0; 1,302,615 7/1962 France 188/166 Hans-Joachim Adelski, Bad Neustadt, Germany Przmary Examiner-Duane A. Reger [21 APPL 725,875 Attorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L. [22] Filed May 1,1968 Lerner and Daniel J. Tick [45] Patented Jan. 12,1971 [73] Assignee Siemens Aktiengesellschaft Munich, Germany and Berlin, Germany, a corporation of Germany {32] Priority May 5, 1967 3:12;; ABSTRACT: A spring set and electromagnetically released friction brake, preferably for electric motors, has an exteriorly M threaded sleeve coaxially spaced from the magnetic armature 54 ELECTROMAGNETlCALLy CONTROLLED disc which is magnetically attracted toward the releasing posi- FRICTION CLUTCH tion. A ring-shaped abutment structure surrounds the sleeve gc m- Figs 1 and is held in an adjusted position relative to the sleeve by means of a ring which is seated on the sleeve in threaded en- [52] US. Cl 188/171, gagemem therewith. o end of each brake pressure spring is 88/166 in ressure engagement with the armature disc. The other end 5 P 1] lift. CI B608 13/04 bears against the abutment structure Rotating the i on the [50] new of Search 188/ sleeve causes the ring to shift axially and thereby also dis- 1711 1661 196M; 192/90 places the abutment structure to adjust the spring force. The threaded ring is prevented from inadvertent rotation by having [56] References cued marginal recesses engaged by leaf springs which are fastened UNITED STATES PATENTS to the ring-shaped abutment structure and are lifted out of the 2,059,028 10/1936 Price 188/171 recesses when a tubular wrench or the like tool is pushed over 3,224,540 12/ 1965 Straub 188/ 1 71X the ring for the purpose of turning it.

' PATENTEU JAAN 2m.

SHEET 1 BF 2 'PATENTED M12197:

SHEET 2 [IF 2 the dimensions of said magnetic air gap, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force.

2. An electromagnetically releasable friction brake, comprising circular brake friction means, an electromagnetic device having an armature disc coaxially adjacent to said friction means and axially displaceable relative thereto for setting and releasing the brake, an exteriorly threaded sleeve coaxially spaced from said disc, a ring-shaped abutment structure surrounding said sleeve, brake pressure springs of which each has one end in pressure engagement with said armature disc and the other end abutting against said abutment structure, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force, said ring having catch recesses along its periphery, and leaf springs mounted on said ring-shaped abutment structure and engageable with said respective recesses for latching said ring against rotation relative to said sleeve.

3. A brake as claimed in claim 2 wherein said ring is accessible from the side of said sleeve facing away from said armature disc for insertion of a tubular tool for turning said ring on said sleeve, and said leaf springs have respective deflectable ends facing towards said same side, so that insertion of a tool causes unlatching of said ring.

4. An electromagnetically releasable friction brake, comprising circular brake friction means, an electromagnetic device having an armature disc coaxially adjacent to said friction means and axially displaceable relative thereto for setting and releasing the brake, an exteriorly threaded sleeve coaxially spaced from said disc, a ring-shaped abutment structure surrounding said sleeve, brake pressure springs of which each has one end in pressure engagement with said armature disc and the other end abutting against said abutment structure, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force, an axially extending guide structure fixed relative to said sleeve, said armature disc being displaceably seated on guide structure, axially displaceable pins having one end engageable with said annaturc disc and extending therefrom toward the side where said sleeve is located, and a manually actuable brake release lever linked to the other end of said pins for axially shifting them to thereby move said armature disc to releasing position.

5. A brake as claimed in claim 4 further comprising a restoring spring in biasing relation to said lever for normally holding it in the position where said lever and said pins are inactive relative to said armature disc.

6. A brake as claimed in claim 1 further comprising a ring of nonmagnetic material coaxially interposed between said armature disc and said brake pressure springs.

7. A brake as claimed in claim 1 further comprising a housing perimetrically surrounding said friction means and said electromagnetic device and having a carrier plate which covers the axial end of said housing, said electromagnetic device and said sleeve and abutment structure being mounted on said carrier plate and forming together therewith a subassembly unit removable as a whole from said housing.

8. A brake as claimed in claim 7 in combination with an electric motor to which said brake housing is coaxially attached, said motor comprising a fan in said housing, and said friction means having a friction disc coaxially secured to said fan and accessible upon removal of said subassembly unit. 

1. An electromagnetically releasable friction brake, comprising circular brake friction means, an electromagnetic device having a magnetic air gap and an armature disc coaxially adjacent to said friction means and axially displaceable relative thereto for setting and releasing the brake, an exteriorly threaded sleeve coaxially spaced from said disc, a free ring-shaped abutment structure surrounding said sleeve, a plurality of brake pressure springs of which each has one end in pressure engagement with said armature disc and the other end abutting against said free abutment structure whereby a variation in the force of said springs and therefore a braking torque may be applied to said armature disc without varying the dimensions of said magnetic air gap, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force.
 2. An electromagnetically releasable friction brake, comprising circular brake friction means, an electromagnetic device having an armature disc coaxially adjacent to said friction means and axially displaceable relative thereto for setting and releasing the brake, an exteriorly threaded sleeve coaxially spaced from said disc, a ring-shaped abutment structure surrounding said sleeve, brake pressure springs of which each has one end in pressure engagement with said armature disc and the other end abutting against said abutment structure, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force, said ring having catch recesses along its periphery, and leaf springs mounted on said ring-shaped abutment structure and engageable with said respective recesses for latching said ring against rotation relative to said sleeve.
 3. A brake as claimed in claim 2 wherein said ring is accessible from the side of said sleeve facing away from said armature disc for insertion of a tubular tool for turning said ring on said sleeve, and said leaf springs have respective deflectable ends facing towards said same side, so that insertion of a tool causes unlatching of said ring.
 4. An electromagnetically releasable friction brake, comprising circular brake friction means, an electromagnetic device having an armature disc coaxially adjacent to said friction means and axially displaceable relative thereto for setting and releasing the brake, an exteriorly threaded sleeve coaxially spaced from said disc, a ring-shaped abutment structure surrounding said sleeve, brake pressure springs of which each has one end in pressure engagement with said armature disc and tHe other end abutting against said abutment structure, a ring seated on said sleeve in threaded engagement therewith and engaging said abutment structure whereby rotation of said ring on said sleeve displaces said abutment structure for adjusting the spring force, an axially extending guide structure fixed relative to said sleeve, said armature disc being displaceably seated on guide structure, axially displaceable pins having one end engageable with said armature disc and extending therefrom toward the side where said sleeve is located, and a manually actuable brake release lever linked to the other end of said pins for axially shifting them to thereby move said armature disc to releasing position.
 5. A brake as claimed in claim 4 further comprising a restoring spring in biasing relation to said lever for normally holding it in the position where said lever and said pins are inactive relative to said armature disc.
 6. A brake as claimed in claim 1 further comprising a ring of nonmagnetic material coaxially interposed between said armature disc and said brake pressure springs.
 7. A brake as claimed in claim 1 further comprising a housing perimetrically surrounding said friction means and said electromagnetic device and having a carrier plate which covers the axial end of said housing, said electromagnetic device and said sleeve and abutment structure being mounted on said carrier plate and forming together therewith a subassembly unit removable as a whole from said housing.
 8. A brake as claimed in claim 7 in combination with an electric motor to which said brake housing is coaxially attached, said motor comprising a fan in said housing, and said friction means having a friction disc coaxially secured to said fan and accessible upon removal of said subassembly unit. 